Reservoir fluids typically exist or are produced at elevated pressures and temperatures, and include a mixture of hydrocarbon gases (e.g., natural gas) and complex hydrocarbon fluids generally referred to as “oil” or “condensate.” There are instances where it is desired to determine properties of a reservoir fluid for reservoir management purposes, such as to determine gas to oil ratios (GOR), fluid shrinkage, American Petroleum Institute (API) gravity, and hydrocarbon composition. These data are utilized widely in reserve estimations, reservoir simulation, pressure transient testing, production allocations, and the like. Although some offshore platforms maintain a small laboratory for determination of basic fluid properties, space on the platform may not permit the equipment necessary to analyze the fluid in detail. In some cases, it is not practical to maintain the voluminous analysis equipment at remote sampling sites, such as deep water offshore platforms, remote locations, underdeveloped countries, and rural areas. Therefore, a sample taken on an offshore platform may be transported to an onshore testing facility. Depending on the location of the offshore platform or rural onshore sampling site, the sample may travel hundreds or thousands of miles to reach the testing facility. Due at least in part to transportation regulations on pressurized petroleum fluids, this travel can introduce a considerable lag between the time the sample is taken and the time the analysis is performed. This time lag can be excessive and in some cases impractical, discouraging frequent testing and reducing or eliminating retesting. The travel increases the likelihood that the sample will become compromised and/or contaminated, and introduces additional expenses related to travel and time into the costs of analysis. If a sample is contaminated or fouled during collection, transport, or otherwise, the contamination or fouling may not be discovered until the sample has traveled the many miles to reach the centralized testing facility. In such cases, when possible, another sample is then taken and transported to the centralized testing facility.
In some cases, the headspace vapor from a liquid, rather than the liquid itself, may be analyzed in a laboratory on an offshore platform. While this approach allows analysis at the site, more information regarding the liquid may be desired. Furthermore, when analysis of reservoir fluids includes flash vaporization, a separate apparatus may be required to flash the sample and collect the liquid and vapor phases, in which case the liquid and vapor phases are typically transferred to another apparatus for compositional analysis. These operations are generally implemented by skilled personnel stationed at the offshore platform.